Estimate the length of the segment

Which one ? is the answer and how to find this answer

Consider a cube that has sides of length l. now consider putting the largest sphere you can inside this cube without any point on the sphere lying outside of the cube. the volume ratio -volume of the sphere/ volume of the cube is 1. 5.2 × 10−1 2. 3.8 × 10−1 3. 1.9 4. 2.5 × 10−1 5. 3.8

The legs of a right triangle measure 6 meters and 8 meters. what is the length of the hypotonuse.